Hibiscus plant named ‘DUP-PTF’

ABSTRACT

A new and distinct cultivar of  hibiscus  plant named ‘DUP-PTF’, characterized by glossy, dark green leaves, upright growth, and large flowers having a medium sized dark red eye which extends about 25 percent of petal length. The outer edge of the eye is interrupted by radial venation, giving the appearance of a ragged edge. Nevertheless, the eye is clearly defined with a definite margin against a light bluish-pink zone which extends to the roughly the petal midpoint, grading into a watermelon red zone which extends to the petal edge, with the underlapping petal edge grading circumferentially to a pinkish orange.

Latin name of the genus and species: Hibiscus rosa-sinensis.

Variety denomination: ‘DUP-PTF’.

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinct cultivar ofhibiscus, botanically known as Hibiscus rosa-sinensis and hereinafterreferred to by the cultivar name ‘DUP-PTF’.

Hibiscus has been the subject of human admiration for centuries. Whilethe ancestry of present rosa-sinensis hybrids is not precisely known,today's hybrids are thought to be the products of interspecific crossesinvolving Hawaiian, Polynesian and Asian species, among others, some ofwhich may no longer be found in the wild, if they are to be found atall. It is thought that the first hibiscus identified as a rosa-sinensiswas a double red form of uncertain origin found in cultivation in China,India and Polynesia, to be later introduced to Hawaii from Polynesia. Itis known to have been grown in Europe during the Victorian era.Eventually, it was introduced to the continental United States where itwas cultivated outdoors in the Deep South as well as in regions havingsubtropical or Mediterranean climates (Florida and Southern California,respectively). Indoor cultivation took place in the temperate regions ofthe U.S. It is speculated that the original rosa-sinensis is actually aspecies hybrid, possibly naturally arising, involving two or morespecies. Regardless, present day hybrids are descended from the originaldouble form, and are thought to include in their ancestry Hibiscusliliiflorus, H. arnottianus, H. schizopetalus, as well as other species,particularly those native to Hawaii.

Today, after decades of extensive hybridization, the moniker“rosa-sinensis” almost certainly denotes complex interspecific hybrids.Such hybrids are usually far removed from their species ancestors inform and color. Flowers characterized by spectacular size, colorintensity and, in the last several decades, ringed and spotted patternshave been produced by U.S. hybridizers in Louisiana, Florida, Hawaii,Texas and elsewhere. Other hotbeds of hibiscus-breeding activity includeAustralia, and more recently, Tahiti. Today's flowers are removed fromtheir species ancestors to such an extent that it is almost impossibleto unravel the species component contributions which comprise a modemhybrid hibiscus.

However, in the past, despite the fact that hybridization was givingrise to flowers of spectacular size and color intensity, very few if anyearly hybrids attracted the attention of large scale commercialpropagators. While the flowers were truly some of the most impressive inthe entire plant world, hybridizers had been selecting predominantly forbloom characteristics. As a result, many of these spectacular hybridswere weak plants which, even with the best care, were short-lived anddifficult to grow. The occasional production of a spectacular bloom wasenough to keep the interest of those truly dedicated to growingsomething rare and special, and thus new hybrids continued to beproduced by hobbyists with abundant passion and small amounts ofgreenhouse space. As a result, more breathtaking varieties were producedeach year, to be distributed via grafting among dedicated hobbyists,only to die out within a time span of 10 or 15 years. It should be notedthat the majority of the varieties introduced in the 1960's, 70's andeven many from the 1980's and 90's are likely to be lost to cultivation,if they are not already.

Progress toward the development of a plant which an average gardenercould easily grow and enjoy was slow to non-existent. Many varietieswere difficult to root from cuttings, and even if they did root, manyvarieties, when grown on their own roots, were extremely susceptible tofungal and bacterial root rots. Some grew acceptably only as graftedplants. However, grafted plants suffer from a serious disadvantage inthat the quality of the graft generally determines the quality of theplant, making the production of uniformly vigorous plants a difficulttask. Furthermore, after several years, it is common for grafted plantsto develop stresses at the graft union due to the unequal growth ratesof the rootstock and the scion. Such stresses can eventually lead toloss of vigor and death of the plant. Moreover, grafting does notcompletely cure the problem of root rot; surprisingly, the rootstock,when grafted to a root rot susceptible scion was generally still morelikely to suffer rot than a plant of the rootstock variety. For example,a plant of “Seminole Pink,” a garden variety commonly used as arootstock, is highly resistant to root rot. However, when Seminole Pinkis used as a rootstock for “Romeo,” a modern hybrid which is prone toroot rot, the grafted plant, while less susceptible than Romeo, is moresusceptible than a plant of Seminole Pink.

Perhaps the most detrimental disadvantage of grafted plants is theintroduction of viruses into the scion from the rootstock. Rootstockvarieties are almost invariably old garden varieties which, over theyears, have become infected with multiple viruses. While the performanceof such vigorous garden varieties may be largely unaffected by virusinfection, the hybrid scion of a grafted plant has generally beensignificantly less vigorous than the garden variety rootstock, and virusinfection from the rootstock resulted in a weak plant. The problem onlyincreased with successive generations of grafting, resulting in a rapidgeneral weakening of a given variety over time.

Because many hybrids are shy bloomers at best, the extra stresses due tovirus infection, grafting, low disease resistance, and the likegenerally gave sparse flower production, as well as a high number ofdeformed blooms. Furthermore, ordinary stresses such as over/underwatering and mite/insect pests resulted in a high percentage of buddrop. The buds of large-flowered hybrids often take relatively longtimes to reach blooming stage, and it was not uncommon to wait withanticipation while a bud swelled day by day, only to be disappointedwhen the mature bud toppled from its pedicel on the day it was to open.

Moreover, because of hybridizer emphasis on the flower, the plant wasoften relatively slow growing and sparsely clothed in leaves. Suchplants usually do not attract purchasers as they do not have theappearance of garden-worthy specimens.

It has been noted in the industry that a hybrid hibiscus seems to sellonly when it is bearing a bloom. The practical effect of all of theabove-mentioned issues on a retail outlet is as follows. A garden centerwill order a number of plants. Many of the plants will arrive either inbloom or up to several days away from blooming. The blooming plants willgenerally sell the first day. On several subsequent days, new bloomswill open on the remaining plants, and some of them will sell as well.However, by the fourth or fifth day, the lack of perfect growingconditions begins to take a toll, and the plants begin to drop theirmost mature buds. From this point on, the plants essentially sit arounduntil they are marked down or even until they decline to such a degreethat they must be discarded.

Such characteristics left hibiscus with the reputation that, despite themesmerizing beauty of the flowers, they were for collectors who had timeto attend to the seemingly exacting requirements of the plants. As aresult, while new varieties were produced by hobbyists yearly,propagation of modern hybrids on a commercial scale was generally rare.Common garden varieties (Seminole Pink, Brilliant, President, PaintedLady, Butterfly, Lagos, for example), which are easy to root, fastgrowing, and tolerant of a wide range of growing conditions were theonly hibiscus widely available. The “exotics” were of little interest tocommercial growers.

Many new varieties of hibiscus representing a vast improvement inrose-sinensis hybrids, have been produced by an intense hybridizingprogram conducted by the Inventor at his commercial nursery inPlaquemine, La. The objective of the program has been to producevarieties of hibiscus which root easily under commercial rootingconditions, grow well on their own roots, maturing rapidly intowell-leaved, salable plants under commercial greenhouse conditions.Further objectives are to produce hibiscus cultivars as aforementioned,having large flowers with unique and desirable flower characteristics,such as size, color intensity and pattern.

Asexual reproduction of the new hibiscus by hardwood, semi-hardwood, andterminal cuttings taken in a controlled environment in Plaquemine, La.,has shown that the unique features of this new hibiscus are stable andreproduced true to type in successive generations.

SUMMARY OF THE INVENTION

The cultivar ‘DUP-PTF’ has not been observed under all possibleenvironmental variables. The phenotype may vary somewhat with variationsin environment such as temperature, light intensity, nutrient and waterstatus without, however, any variation in genotype. For example, duringcooler weather, flowers of many hibiscus cultivars may demonstrate anincreased intensity in pink tones. Furthermore, as with many varietiesof hibiscus, cooler weather can result in a decrease in flower diameter,and a corresponding reduction in size of sepals and pistil. Moreover, asindicated below, plant characteristics vary greatly with culture, withinternode spacings often increasing in warmer weather and with highersoil fixed nitrogen content. Plants grown at higher temperatures alsoexhibit a faster rate of growth. In general the plant used in thefollowing description was grown at temperatures which never dipped below55° F. Because the Inventor's one gallon pot plants are grown for anaverage time of about 5.5 to 6 months prior to sale, and the 10 inch potplants are grown for an average time of about 7 to 8 months prior tosale, it is difficult to provide a precise temperature profile requiredto give the average plant measurements described in the belowdescription. The growing period can encompass several seasons, withseasonal fluctuations in high/low temperatures as well as photo period.It is expected that the daily high temperature ranged from about 70° F.to about 95° F., and the daily low temperature, which never dipped below55° F., ranged from about 65° F. to about 80° F.

The following traits have been repeatedly observed and are determined tobe the unique characteristics of ‘DUP-PTF’. These characteristics incombination distinguish ‘DUP-PTF’ as a new and distinct cultivar.

-   -   1. Glossy, dark green leaves.    -   2. Upright habit appropriate for container production and        culture.    -   3. Freely flowering habit.    -   4. A large flower characterized by a medium sized dark red eye        which extends approximately 25 percent of petal length. The        outer edge of the eye is interrupted by radial venation, giving        the appearance of a ragged edge. Nevertheless, the eye is        clearly defined with a definite margin against a light        bluish-pink zone which extends to the roughly the petal        midpoint, grading into a watermelon red zone which extends to        the petal edge, with the underlapping petal edge grading        circumferentially to a pinkish orange.    -   5. The plant is more free-flowering and has also been found to        root more easily under greenhouse conditions than either parent,        particularly the seed parent, ‘Patrick’. ‘DUP-PTF’ has also been        observed to have stronger growth and higher resistance to root        rot (when grown un its own roots) than ‘Patrick’. Chromatically,        it is a stronger, more compelling color (a bright watermelon)        than its pollen parent, ‘Light My Fire’ (a muted orange-tone).    -   6. ‘DUP-PTF’ is from the inventor's breeding program which has,        since 1998, focused on the qualities of the plant in addition to        those of the flower. Seedlings with outstanding blooms are        usually eliminated from his breeding program if the plant is not        an improvement in form, heat performance or free-flowering        nature. His program is the only one, to his knowledge, which        rigorously trials large numbers of a given seedling variety        under punishing conditions of high heat and humidity (southern        Louisiana), generally culling of all but the best performers.        Plants which meet the standards of the program, such as DUP-PTF,        generally exhibit, with respect to other exotics (i.e.,        non-garden variety types), one or more of the following        characteristics: better plant proportions, better leaf coverage,        stronger growth, a more free-flowering nature, than exotic-type        varieties presently available. Such varieties include otherwise        excellent exotic-type varieties such as ‘Northern Lights’,        ‘Amber Suzanne’, ‘Palomino’, ‘Crossfire’, and ‘Red Cadillac’.

BRIEF DESCRIPTION OF THE PHOTOGRAPH(S)

The accompanying colored photographs illustrate the overall appearanceof the new hibiscus, showing the colors as true as it is reasonablypossible to obtain in colored reproductions of this type.

The photograph on the first sheet (FIG. 1) depicts a first day flower of‘DUP-PTF’ about an hour after fully opening in March in Plaquemine, La.

The photograph on the second sheet (FIG. 2) depicts the reverse of thebloom in FIG. 1.

The photograph on the third sheet (FIG. 3) depicts the flower profile,showing the relative proportions of the pistil and bloom diameter of thebloom in FIG. 1. The calyx is clearly visible.

The photograph on the fourth sheet (FIG. 4) depicts one plant in astandard one-gallon nursery pot.

The photograph on the fifth sheet (FIG. 5) depicts a mature leaf.

DETAILED BOTANICAL DESCRIPTION

In the following description, color references are made to The RoyalHorticultural Society Colour Chart, Edition V, version 2, except wheregeneral terms of ordinary dictionary significance are used. Thefollowing observations, measurements, and values describe plants grownin Plaquemine, La., in a standard one-gallon nursery pot. Plants usedfor the description were approximately 26 weeks old.

-   Botanical classification: Hibiscus rosa-sinensis.-   Parentage:    -   -   Female or seed parent.—‘Patrick’ (not patented).        -   Male or pollen parent.—‘Light My Fire’ (U.S. Plant Pat. No.            22,466).-   Propagation:    -   -   Type.—‘DUP-PTF’ has been propagated by taking hardwood,            semi-hardwood and tip cuttings, with semi-hardwood            preferred. It should be noted that many methods of asexual            propagation, such as tissue culture and other cloning            processes, can be expected to show some degree of success in            the propagation of the present cultivar. However, of the            methods tried by the Inventor, the use of semi-hardwood            cutting has given the greatest yield of commercially salable            plants. Asexual propagation has resulted in plants which            have the flower and plant characteristics of the original            ‘DUP-PTF’ plant, and thus the variety is stable. Cuttings            from ‘DUP-PTF’ generally root well under commercial            greenhouse conditions. While greenhouse conditions such as            relative humidity and other factors such as cutting age            prior to planting affect the take, it is not unusual to get            a take of almost 100%. Please note that as successive            generations of cuttings are raised, the raiser may            experience a drop in take due to the incorporation of virus,            particularly if at some point grafted plants are prepared,            and cuttings are taken from such a plant.        -   Time to initiate roots.—An average time of initiation at            approximately 22° C. is approximately six weeks, with            slightly longer times during winter at comparable            temperatures, and slightly shorter times during summer at            comparable temperatures.        -   Time to develop roots.—An average time, at approximately 22°            C., of development of a root system after initiation, is            approximately six weeks, with slightly longer times during            winter at comparable temperatures, and slightly shorter            times during summer at comparable temperatures. It should be            noted that root initiation and development can be affected            by greenhouse conditions, biological stressors such as            disease organisms, as well as environmental stressors such            as low or variant relative humidity, over- and            under-watering, temperature variations or high or low            constant temperatures. Thus, rooting times can be shorter or            longer than the times given above depending on the values of            many different characteristics during the rooting process            known in the art.        -   Root description.—Fibrous and well-branched.-   Plant description:    -   -   Plant form and growth habits.—Perennial evergreen having            strongly upright growth. The growth habit is less compact            than many other varieties. As recognized by one of skill in            the art, internodal distance can be dependent upon            greenhouse temperature/time profile, fertilizer availability            profile, and other factors.        -   Branching habit.—Moderately well-branched, developing            approximately 2-5 laterals when a single stem plant is            pinched back to a 5 inch height.        -   Plant height, soil level to top of flowers.—A salable plant            in a standard one-gallon nursery pot can be approximately 18            inches high and 17 inches wide. Please note that cultural            variables such as those mentioned under “Plant form and            growth habits,” above, among others, can cause significant            variation from the values given herein.        -   Lateral branch description.—The average branch            characteristics of a salable plant grown in a standard            one-gallon nursery pot. Average Length: Approximately 14″.            Average Diameter: Approximately 0.75 cm measured at the            transition from green to woody stem texture. Texture:            Immature: Smooth. Mature: Woody and rough. Mature branch            color: 148D. Immature branch color: 147A.-   Mature foliage description:    -   -   Arrangement.—Alternate, single, numerous, symmetrical.        -   Length.—Approximately 11.5 cm.        -   Width.—Approximately 10 cm.        -   Shape.—Ovate to cordate.        -   Apex.—Acute.        -   Margin.—Crenate entire.        -   Upper surface.—Glabrous, rugose.        -   Lower surface.—Scabrous.        -   Color.—Young foliage, upper surface: More green than 140A;            glossy. Mature foliage, upper surface: Generally darker than            140A; glossy.        -   Petiole.—Average Length: 5.5 cm. Average Diameter: 0.3 cm.            Texture: Very fine pubescence on upper surface; lower            surface, glabrous. It should be noted that as with other            plant growth characteristics, foliage color and size can            vary with nutrient availability, greenhouse temperature, day            length, and other conditions of culture.-   Flower description:    -   -   Natural flowering season.—Year round, with number and size            reduction in extended periods of cold weather, such as            daytime temperatures of less than 60° F. Extreme heat can            slow growth and flower production.        -   Flower arrangement.—Flowers arranged singly at terminal leaf            axils. Very free-flowering, with usually three to five            developing flower buds per lateral branch, flowers generally            face outward or downward.        -   Flower appearance.—Large single bloom. Flowers are open for            one to two days before senescence, which is often            accompanied by partial or full petal closure. Flowers            persistent.        -   Flower diameter.—‘DUP-PTF’ flowers are generally in the            range of from about 7″ to 9.5″ when fully open, with largest            flowers produced during warm weather (for example, day and            night time temperatures above 73° F.).        -   Flower depth.—Flower depth was measured to average            approximately 4.8 cm. Flower depth was measured after            removal of a petal and a sepal to expose the base of the            pistil. The measurement was taken on a fully opened flower            in the direction of the pistil, from the base of the ovaries            to the maximum height of the flower petal. The depth was            measured by using the point of recurvature of the petal            whorl. It should be noted that outermost whorl of hibiscus            blossoms can flatten out during the day, or increase or            decrease in curvature or degree of petal reflex during the            day, and thus variance from the foregoing value is possible.        -   Flower bud (just before showing color).—Rate of opening: 1-2            days. Rate of opening is generally faster in warmer weather.            Flower bud dimensions were measured on a bud which was            approximately one day from opening. Bud length was measured            from the tip of the bud to the abscission zone where bud and            peduncle meet. The average length of a bud which is one day            from opening is approximately 8.6 cm. Bud diameter was            measured at the widest part of the bud, an area            approximately halfway up the outside of the developing            petals. The average diameter of a bud which is one day from            opening is approximately 3.6 cm. It should be noted that bud            dimensions can vary somewhat with cultural conditions, and            variations can even be observed in buds which are at the            same stage of development. Shape: Roughly conical to long            ovoid.        -   Petals.—Upper Surface Texture: Smooth, satiny, rugose. Lower            Surface Texture: smooth, rugose. Arrangement: The corolla            consists of five petals arranged in a whorl, having regular            partial overlap, even when the flower is fully open. Shape            of a petal from the outer whorl: Roughly spatulate, with a            rounded apex and a truncate base. The margin of each petal            is undulate and entire, such that the margin of the flower            appears to be undulate, and the overlap is such that the            flower margin appears circular, with small indentations at            the point where the flower margin changes from one petal to            the adjacent petal. A representative petal length was            measured to be about 10.4 cm, and was taken from the base of            the petal to the farthest point on the margin opposite the            base. A representative width is 9.4 cm, and was measured            perpendicularly to the pistil at the widest point of the            petal. Petal size can vary with cultural conditions, such as            temperature, and thus the flower size and shape can vary as            well. Often, flowers which are produced at colder            temperatures are smaller and appear more fully overlapped,            giving almost a wheel-shaped appearance. When fully open,            the edges of ‘DUP-PTF’ flowers can be recurved. The color of            a warm weather flower is described below. It has been            observed that variations in temperature can effect the            stronger or weaker expression of certain pigments, changing            the balance of color, and thus variations in color intensity            and pattern can occur with temperature. Cold weather may            intensify pink coloration. It should be noted that the            colors of hibiscus are among the most changeable of all            flowers. A newly opening morning bloom generally has the            most intense coloration, but as the flower flattens out and            is exposed to the sun, many pigments begin to fade            immediately, resulting in a flower which can look like a            different variety altogether. While the flower of ‘DUP PTF’            fades less than those of many other varieties, exposed to            strong sun, it can fade to a soft pink with a uniform soft            yellow by the end of the first day. The morning colors are            described below. Color: Upper surface: Medium sized 53A eye            which extends 25 percent of petal length, sharply margined            with a 39D intermediate zone which grades into a 49D zone            which grades into a 33A petal margin. Lower surface: Uniform            37C, shading to 8C on overlapping side of petal.        -   Sepals.—Unlike the petals, sepals are relatively invariant            in color. Their size can be affected by the same cultural            conditions which affect flower size. They are generally            smooth and elongated oblong with acute apices (pointed            tips). They are fused at the long edges into a cupped calyx            bearing at its brim the five pointed tips. When the petals            of the flower spread open, the five pointed tips, which are            flush with the backs of the opening petals, are forced into            a radiating five point star-shaped configuration, which can            be observed on the profile and reverse pictures. A            representative width, which is measured perpendicularly to            the long axis of the sepal at the position on the sepal at            which the oblong edges transition from fused to unfused, is            approximately 1 cm. A representative length, measured on the            sepal from the free point to the fused point is            approximately 2.9 cm. Color: Upper surface: Close to 146A.            Lower surface: Close to 147A.        -   Peduncle.—Length: 5.0 cm. Angle: Approximately 40 degrees            from branch. Strength: Strong, flexible. Texture: Smooth.        -   Reproductive organs.—Androecium: Stamen number:            Approximately 90. Anther shape: Crescent. Anther color: 10D.            Amount of pollen: Moderate. Pollen color: 16A. Gynoecium:            Pistil number: 1. Pistil length (from base of ovaries to top            of stigma): 10.0 cm. Style length (from base of ovaries to            stigma branching point): 9.4 cm. Style diameter, at base:            0.8 cm. Style color: Base of 53A, vertically striped on            style to lowest anthers, over 39C. Stigma number: 5. Stigma            color: 46A. The epicalyx is situated below the calyx and            bears an average of about 6 to about 9 slender projections,            although sometimes more or less, which are shorter than the            tepals, and which radiate from a common point. The color is            approximately 140A. It should be noted that the dimensions            of a hibiscus blossom generally change not only during bud            development, but also during opening, as well as during the            life of the opened flower. For instance, upon opening, the            petals generally gain in length. Furthermore, after opening,            the pistil continues to grow in length while the anther            filaments which hold the pollen sacs increase in length, the            pollen sacs open and the stigmas separate, each at the tip            of a branched style structure. Toward the end of the flower            life, possibly due to a reduction in turgor pressure, the            pistil may shrink in length and the petals may slightly            decrease in area. Usually, the senescing petals of the            flower fold toward the pistil to some degree, in some cases,            completely enfolding it. In Baton Rouge, and likely, all            locations, seed pods are generally not produced unless the            flower is hand pollinated, regardless of whether the plant            is outside or in the greenhouse. Even if hand pollinated,            the “take” depends upon the pollen parent, with cooler            periods of the year (Fall, Spring) giving the greatest            probability of success. Under most conditions and care            regimens, the formation of a seed pod is unlikely, even if            hand pollinated, but it can occur. In general, the            rosa-sinensis seed pod is a five-chambered okra-type fruit            with the long seed chambers disposed along the main axis of            the flower. Up to about 50 viable seeds can be produced, but            the typical yield is usually about 15 or fewer.-   Disease resistance: ‘DUP-PTF’ has not been observed to be resistant    to pathogens common in hibiscus. However, it has been observed in    the green house to have a higher resistance to root rot than that of    many existing hybrid varieties grown on their own roots. If desired,    and if the risk of virus infection is of no concern, the present    variety can be grafted onto a rootstock and be grown as a grafted    plant.

Hibiscus rosa-sinensis is not frost hardy, although occasionally,established plants may come back from the roots and stem bases afterexposure to overnight temperatures as low as about 20° F. Gardenvarieties are more reliable than the exotic types in this regard.However, most exotic varieties will be severely damaged by several hoursof exposure to about 28° F. Baton Rouge is in USDA Hardiness Zone 9 andexotic hibiscus which have been in the ground for several years oftensurvive average winters by regrowing from stem bases.

It is claimed:
 1. A new and distinct hibiscus plant named ‘DUP-PTF’,either grafted or on its own roots, as illustrated and described.